File:Animal and vegetable physiology, considered with reference to natural theology (1836) (14741766556).jpg

Identifier: animalvegetable01roge (find matches)
Title: Animal and vegetable physiology, considered with reference to natural theology
Year: 1836 (1830s)
Authors: Roget, Peter Mark, 1779-1869
Subjects: Biology Physiology Plant physiology Natural theology
Publisher: Philadelphia, Carey, Lea & Blanchard
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

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eposited in succession; each new^ layer is agglutinatedto the inner surface of the preceding; and each has the shape RUMINANT QUADRUPEDS. 355 of a hollow cone, occupying the part towards the apex ofthe former cone, and extending farther towards the base.Hence a longitudinal section of the whole presents the ap-pearance represented in the annexed figures (218*,) whereA is the section of the horn of an Ox, and b, a similar sec-tion of the horn of an Antelope. C is a magnified view ofthe extremity of the latter, together with a portion of thebone D, which occupies the axis of the horn. In this process of the formation of horn, as happens inthat of shells, there sometimes occur irregularities, or peri-odical intermissions and increase of action in the secretingorgans, giving rise to transverse grooves, or ridges. Tliesemay be seen in the horns of the goat, in which the fibresare short, and laid one over another with the same regula-rity as the tiles of a house. The tendency in these horns
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to assume a spiral form is explicable on the same principlesas those which regulate the growth of turbinated shells. 356 THE MECHANICAL FUNCTIONS. The horns of the ox and of the antelope tribes are formedof longer and more continuous fibres, which are closelycompacted together, and exhibit very distinctly the seriesof hollow cones of which they are composed. The horns of the Rhinoceros, both of the one and twohorned species, grow from the integument covering thenose, to which they adhere without having any connexionwith the subjacent bones. They have a pyramidal shape,and are composed of parallel fibres, resembling hairs, agglu-tinated together into a solid mass by a material which actsas a cement. This fibrous structure is most distinctly seenat the base of the horn, where the ends of the fibres project,like those of a brush, from the surface. When these hornsare sawn transversely, and examined with a magnifyingglassy a great number of orifices are seen, marking theempty spaces that

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